tailieunhanh - Standard Practice for classification of soils and soil-aggregate mixtures for highway construction purposes

Standard Practice for classification of soils and soil-aggregate mixtures for highway construction purposes practice covers a procedure for classifying mineral and organomineral soils into seven groups based on laboratory determination of particle-size distribution, liquid limit, an plasticity index. It may be used when precise engineering classification is required, especially for highway construction purposes. Evaluation of soils within each group is made bymeans of a group index, which is a value calculated from an empirical formula.  | Standard Specification for Classification of Soils and Soil-Aggregate Mixtures for Highway Construction Purposes I AASHTO Designation M 145-91 2004 1. SCOPE . This recommended practice describes a procedure for classifying soils into seven groups based on laboratory determination of particle-size distribution liquid limit and plasticity index. Evaluation of soils within each group is made by means of a group index which is a value calculated from an empirical formula. The group classification including group index should be useful in determining the relative quality of the soil material for use in earthwork structures particularly embankments subgrades subbases and bases. However for the detailed design of important structures additional data concerning strength or performance characteristics of the soil under field conditions will usually be required. . The values stated in SI units are to be regarded as the standard. 2. REFERENCED DOCUMENTS . AASHTO Standards Til Materials Finer Than 75-pm No. 200 Sieve in Mineral Aggregates by Washing T 27 Sieve Analysis of Fine and Coarse Aggregates T 87 Dry Preparation of Disturbed Soil and Soil Aggregate Samples for Test T 88 Particle Size Analysis of Soils T 89 Determining the Liquid Limit of Soils T 90 Determining the Plastic Limit and Plasticity Index of Soils T 146 Wet Preparation of Disturbed Soil Samples for Test . ASTM Standard D 1140 Amount of Material in Soils Finer Than the No. 200 75-pm Sieve Note 1 Either AASHTO T 88 or T 11 and T 27 or ASTM D 1140 will be used to determine the particle size distribution of soils or soil-aggregate mixtures as a basis for classification. X CLASSIFICATION . The classification is made by using the test limits and group index values shown in Table 1. If a more detailed classification is desfred a further subdivision of the groups shown in Table 1 may be made. An example of the classification with such subgroups as shown in Table 1 may be made. An example of the .